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The Quantum Experiment That Simulates a Time Machine
KentuckyFC writes One of the extraordinary features of quantum mechanics is that one quantum system can simulate the behaviour of another that might otherwise be difficult to create. That's exactly what a group of physicists in Australia have done in creating a quantum system that simulates a quantum time machine. Back in the early 90s, physicists showed that a quantum particle could enter a region of spacetime that loops back on itself, known as a closed timelike curve, without creating grandfather-type paradoxes in which time travellers kill their grandfathers thereby ensuring they could never have existed to travel back in time in the first place. Nobody has ever built a quantum closed time-like curve but now they don't have to. The Australian team have simulated its behaviour by allowing two entangled photons to interfere with each other in a way that recreates the behaviour of a single photon interacting with an older version of itself. The results are in perfect agreement with predictions from the 1990s--there are no grandfather-type paradoxes. Interestingly, the results are entirely compatible with relativity, suggesting that this type of experiment might be an interesting way of reconciling it with quantum mechanics.
> The results are in perfect agreement with predictions from the 1990s--there are no grandfather-type paradoxes.
There is no time travel citizen! Go on about your lives.
Meanwhile the military starts researching chrono-troops. Because, you know, Australia has always controlled the world with its benevolent Empire...
This isn't news. They already did the same experiment in January 2015.
/. posts from Colorado have gotten stranger and stranger...
"Various physicists have discovered solutions to Einstein’s field equations that contain loops that return to the same point in space and time."
What a lazy bit of reporting! Mr. Kurt Friedrich Gödel first discovered the Einstein's general relativity allowed for closed timelike curves. He presented a paper describing this solution to Einstein as a birthday present, while they were both working at the IAS. It grieves me when Gödel is not given the recognition he is certainly due.